There exists a wide variety of surface modification processes for use in conjunction with metallic materials, including diffusional processes, coatings, and mechanical and thermal treatments. U.S. Pat. No. 3,100,724 to C. F. Rocheville, for example, describes an apparatus for coating a surface with metallic powders or lubricating particles, as well as the use of glass beads to abrade a surface. In 1990, a paper by A. P. Alkhimov et al described what is called a cold gas-dynamic deposition process, in which they claimed to be able to deposit a thick layer of aluminum onto a substrate using air or a mixture of helium and air at high pressure accelerated through a supersonic nozzle. In 1994 Alkhimov et al received U.S. Pat. No. 5,302,414 for a method and an apparatus for a "Gas-Dynamic Spraying Method for Applying a Coating," which they claimed would produce thick layers of a number of metals and metal alloys onto metals, ceramics and glass without heat insulation. Follow-up work produced reasonably thick coatings of Al, Cu on aluminum on alumina, steel on aluminum and Ni--Cr/Cr3C2 on Ti6Al-4V. A 1995 paper by H. Gabel describes a kinetic energy implantation technique, which produces kinetic energy metallization and kinetic energy polymerization to produce metal and polymer coatings, respectively. The inventor, however, describes the coatings as hard, non-conductive surfaces on polymers and metals.
For a great number of polymeric materials, the relative inertness and poor thermal stability of the surface make the materials unsuitable for such surface modification techniques. In particular, the application of electrostatically-based powder coatings to many polymers requires a conductive surface which is often difficult and costly to produce. The need remains, therefore, for a surface modification technique which may be readily applied to polymers and/or ceramic surfaces.